A connection terminal of this type is described in European Patent No. 0 511 098. It includes a metallic component which is affixed in a space of a housing and forms at least one connection unit having a convex hexagonal shape, and having a slit along one of its diagonal planes. The slit is used to hold the wire and to cut through the insulation in order to contact the conductor core. The slit has a widened mouth for cutting through the wire insulation with cutting edges.
U.S. Pat. No. 5,154,633 describes an insulation piercing connecting device for the penetration contacting of a conductor. The device includes a plurality of contact points of the same height which are arranged, one after another, in a direction of the conductor axis. The contact points are designed as swords which penetrate to the same depth into the conductor during the contacting operation. This design of contact points is not suitable for contacting conductors having different cross-sections.
British Patent No. GB 2 210 734 describes a contacting method in which a contacting element having teeth is used. No points are used for the contacting, but, rather, variably high cutting edges along the side at each tooth. Upon insertion of the conductor, the cutting edges rip open the insulation and contact the actual conductor core.